Chapter 11. Bit interleaved coding and modulation in next generation DVB-NGH

International audienceThis chapter describes the main features of the Bit-Interleaved Coded Modulation (BICM) module in the DVB-NGH standard. It is derived from a sub-set of DVB-T2 BICM components, intended to lower receiver complexity and power consumption, with additional features for increased receiver robustness over mobile reception. In order to reduce receiver complexity, only the short Forward error correcting (FEC) block size (Nldpc = 16200 bits) is allowed, the size of the time interleaver memory is halved compared to DVB-T2, the use of rotated constellations is prohibited in 256-QAM and the maximum data bitrate is limited to 4Mbit/sec. On the other hand, higher robustness and coverage are sought through the introduction of improvements at the FEC code level with the adoption of code rate values uniformly distributed over the range 1/3 to 11/15, and at the constellation level with the adoption of non-uniform 64- and 256-QAM constellations and 4-dimensional rotated QPSK constellations. Moreover, the set of interleavers was modified in order to better exploit time diversity: a parity bit interleaver is now adopted for all constellation sizes, an enhanced I/Q component interleaving and a convolutional inter-frame time interleaving have been defined and adaptive cell quantization is to be used in the time interleaver. The chapter finally provides some performance results allowing this new system to be compared with the first generation system, DVB-H